In 2011, archaeologists in the Jerimalai cave in East Timor discovered the world's oldest known fish hook—a shell hook between 16,000 and 23,000 years old. Thus, this essential tool has been in use for millenium to catch fish. Indeed, in 2005 the fish hook was chosen by Forbes as one of the top twenty tools in the history of mankind.
There are an enormous variety of fish hooks. Sizes, designs, shapes, and materials are all variable, depending on the intended purpose of the fish hook. Fish hooks are manufactured for a range of purposes from general fishing to extremely limited and specialized applications. Fish hooks are designed to hold various types of artificial, processed, dead or live baits (bait fishing); to act as the foundation for artificial representations of fish prey (fly fishing); or to be attached to or integrated into other devices that represent fish prey (lure fishing).
To easily discuss hooks, one should be familiar with the established nomenclature. The parts of a fish hook are: its point—the sharp end that penetrates the fish's mouth or flesh; the barb—the projection extending backwards from the point, that secures the fish from unhooking; the eye—the end of the hook that is connected to the fishing line or lure; the bend and shank—those portions of the hook that connects the point and the eye; and the gap—the distance between the shank and the point and the throat—the depth between the point and the bottom most portion of the bend. See e.g., FIG. 1.
Hooks are commonly designed as either single hooks—a single eye, shank and point; double hooks—a single eye merged with two shanks and two points; or triple hooks—a single eye merged with three shanks and three evenly spaced points. Double hooks are formed from a single piece of wire and may or may not have their shanks brazed together for strength. Triple hooks are typically formed by adding a single eyeless hook to a double hook and brazing all three shanks together. Double hooks are used on some artificial lures and are a traditional fly hook for Atlantic Salmon flies, but are otherwise fairly uncommon. Triple hooks are used on all sorts of artificial lures as well as for a wide variety of bait applications.
The hook point is probably the most important part of the hook. It is the point that must penetrate fish flesh and secure the fish. The profile of the hook point and its length influence how well the point penetrates. The barb influences how far the point penetrates, how much pressure is required to penetrate and ultimately the holding power of the hook. Historically, many ancient fish hooks were barbless, but today a barbless hook is used to make hook removal and fish release less stressful on the fish.
Hook sizing can be a bit confusing. Hook sizes with a number followed by a zero increase in size as the number goes up. For instance a 4/0, (“four bar oh or “four oh”), hook is one size up from a 3/0, which is one size up from a 2/0, etc. Hook sizes not followed by a zero, decrease in size as the number increases. For example a size 3 hook is smaller than a size 2 hook, which is smaller than a size 1 hook.
Hooks marked ‘2x strong’ are made from wire as thick as the next size up. A 3x hook is as thick as a hook two sizes up. These hooks are designed to provide as much strength as a hook one or two sizes up, but are used where a smaller hook is required. Extra strength hooks are often used when live-baiting, to avoid having too much hook visible to the fish. They are also useful on lures, where using a bigger hook might kill the action of the lure and make it less attractive to fish. In both these scenarios the extra strength of the smaller hook equates to a larger size hook.
The other common x standard is the length of the hook shank. A ‘2x long’ hook has a shank twice as long as the standard hook of the same size. A 3x long hook has a shank 3 times as long as the standard sized hook. ‘X’ long are hooks mostly found in fly-tying hooks.
The two most important dimensions of a hook are its gape, the distance between point and shank, and the depth of the throat. Generous dimensions ensure deeper penetration of the point and better holding power of the fish.
A less common, but important variant are ‘wide gape’ hooks. A wide gape hook is one where the gape (the gap between the hook point and hook shaft) is wider than the standard hook. Sometimes the wide gape hook is described as ‘2x wide’, and the hook should have a gape twice as wide as the standard hook, or in some cases the same size gape as the next hook size up—but there is little standardization in this area, even amongst hooks from the same manufacturer.
Hooks come in around nine point variants and all are designed to achieve different objectives. See FIG. 2. A knife edge point is designed to cut into flesh and bone, and is useful for most ‘hard’ mouthed fish. But they do have the disadvantage of cutting in and out. A needle point hook is pretty much what it looks like, a needle. Needle points have good penetration, but not as good as knife edge hooks. However, needle points do not cut once in the fish's mouth and are less likely to cut their way out.
Barbless hooks are just that, and can be in any point variant. ‘Micro’ barbs are very small barbs that are mainly seen on small hooks for trout and coarse fishing. A ‘short’ barb hook is a barb nearer the hook point than on a standard hook.
A ‘beak’ hook is where the point of the hook curves up towards the shank, in front of the barb. ‘Kirbed’ or ‘reversed’ hook points are points that curve away at an angle to the shank. They are said to provide a better hook-up rate as the point does not get deflected by the shank. Most people call all hooks like this ‘kirbed’ hooks, but strictly speaking a kirbed hook point bends out to the right looking straight-on to the shaft, and the reversed hook point bends out to the left.
Standard hooks are made from wire that is bent into shape, then the point sharpened and barb added. The wire retains its round shape throughout the hook. To strengthen the metal, hook makers often cold-forge or compress saltwater hooks, and then they're tempered or heat-treated. This is the most crucial stage of hook making. The tempering molecularly alters the metal, concentrating the carbon and removing impurities. Forged hooks, once the shape has been made, have the sides of the shank and bend flattened which makes them much stronger than standard hooks, but a good deal more expensive. They are commonly used in big game fishing where hook strength is vital, but many trophy hunters and competition fishers use them in salt and fresh water fishing as well.
The eye of the hook can also vary. Common types of hook eyes are shown in FIG. 3, and include the ringed eye, brazed eye, tapered eye, looped eye, and the needle eye. As an alternative to the eye, a “spade end” or “flattened” hooks can be used, where the end of the shank is flattened, and the fishing line is snelled/tied directly to the shank of the hook. The flattened area stops the knot from sliding off the hook. The flattened eye is used for medium-sized species in commercial fishing. Where natural bait is used, a hook may possess no eye at all, but simply a flattened end. Spade end hooks are extensively used by match anglers.
In addition, the position of the eye can vary, depending on the shape or curvature of the shank. FIG. 4 shows common eye positions, which is an important factor when it comes to improving the hooking potential of artificial lures. “Straight” is the standard eye position. But other variants include the turned up eye, the turned down eye, and the parallel eye, which is parallel to the hook bend.
There are also variations in shank curvature. See FIG. 5. The shank is the leg of a hook that extends from the bend up to the eye. Hook shanks are manufactured in many different shapes. The most commonly used are the straight shank, curved shank and sliced shank. Shanks are often curved for specific reasons, e.g. to accommodate a special fly imitation. Various fly hooks require the shank to be shaped so as to imitate the body of a special insect. The sliced shank has one or more bards along the shank. These are used to anchor baits, such as worms and soft baits.
As mentioned, double fish hooks are known. In the double hook, the hooks are typically set at about 45-120° from each other, rather than being directly opposed (180°). In addition, the hook, barb, bend and shank of each hook portion are typically in a single plane. However, such hooks have the disadvantage that the hook can slide after it is set and tear the fish's mouth under pressure thus becoming dislodged resulting in the loss of the fish.
Although an ingenious ancient invention, fish hooks can always be improved. Thus, what is needed in the art are better fish hooks, preferably double fish hooks that are less likely to pull out of the fish, especially hooks that can be utilized with a slight offset in opposite directions, this would essentially create a wedge as each hook would pull against each other and would be virtually unable to slide when pressure was applied or when a fish tried to dislodge the hook by shaking its head.